Wireless communications have become prevalent in society. With such widespread use, it is desirable to design communication devices that are lightweight, have a small footprint with a minimum amount of internal components, and that are cost effective to produce, resulting in devices that are inexpensive and easy for the consumer to carry.
To reduce the size of such communication devices, it is desirable to maintain continuous (or almost continuous) bi-directional data transfer between two (or more) devices that are in communication with each other (e.g., full duplex operation). For full duplex operation, a device might utilize frequency diversity where the device transmits on a first frequency range (or band) and receives on a second frequency range (or band). The frequencies used can be separated by an adequate guard-band so that frequency-selective filters can be used to isolate the receiver from the transmitter while, at the same time, coupling both the receiver and the transmitter to a common antenna (also referred to as frequency diplexing). Other techniques utilized to separate the transmit signals from the receive signals for full duplex operation, over a single antenna, include time diversity techniques, spread spectrum codes, polarization selectivity, and circulators.
An issue associated with wireless communications relates to co-site interference wherein communications from devices within a geographic region interfere with other devices in the same geographic region. A solution for co-site interference issues is the quasi-circulator. However, a problem with conventional circulators and quasi-circulators is that such devices can be bulky and can have a narrow frequency range and thus, are not practical in use. Even if the circulator has a small size and a wideband frequency range, a problem that arises is that there might not be enough isolation between ports of the circulator. Another problem can be a circulator that has a narrow tuning range and thus, has a limited tuning bandwidth.
Additionally, conventional communication devices utilize a multitude of internal components. For example, radio frequency (RF) devices utilize power amplifiers, low noise amplifiers, switchplexer, and discrete components. These internal components increase the cost for RF-front end and can also increase the size (and weight) of communications devices.
The above-described deficiencies of today's radio frequency device architectures are merely intended to provide an overview of some of the problems of conventional systems, and are not intended to be exhaustive. Other problems with conventional systems and corresponding benefits of the various non-limiting embodiments described herein may become further apparent upon review of the following description.